Detailed design of the formation, structures and tunnels of a section of the Basque High Speed Line (also known as Basque Y) at Bergara in the province of Guipuzkoa.

The Basque Y is a most challenging project. This high-speed interlink between the three Basque capital cities of Bilbao, Vitoria and San Sebastian will also provide high-speed rail service to Madrid and to the French border.

Main features of the section:

  • Double-track section, with a length of 3.16 km, for passengers and freight.
  • Design speed: 240 Km/h
  • Track gauge: 1,435 m
  • Formation width: 14.00 m
  • 4 bridges:
    • Viaduct over the Olzaileko Stream. Pre-stressed concrete box girder. Length: 100 m (spans: 30-40-30 m). Shallow foundations.
    • Viaduct over the Altzeta Stream. Pre-stressed concrete box girder. Length 140 m (spans: 30-40-40-30 m). Shallow foundations.
    • Lamiategi Viaduct. Prestressed concrete box girder. Length: 425 m (spans: 30 – 9 spans of 40 m – 35 m). Shallow foundations and piled foundations.
    • Viaduct over the Deba River. Composite box girder. Length: 900 m (spans: 50-10 spans 80 m-50 m). Shallow foundations and piled foundations.
  • 3 cut and cover tunnels:
    • Loidi Tunnel. Length: 123 m. Cross- section: 85 m2.
    • Aldai- Azpikua Tunnel. Length: 90 m. Cross- section: 85 m2.
    • Azkarruntz Tunnel. Length: 576m. Cross- section: 100 m2.
  • Main quantities include 2,454,230 m3 of excavation/grading, 647,625 m3 of earthworks and tunnel fill, 1,777 m3 of drainage materials, 16,412 m3of rock fill, 13,866 m3 of selected soil, 12,339 m3 of aggregate, 6,646 m3 of prepared subgrade, 3,007 m3 of sub-ballast, 128,711 m3 of concrete, 18,359,328 kg of steel.


Euskal Trenbide Sarea (ETS)

Project Dates



IDEAM, S.A. (35%)

Project Figures

Amount of contract:
1.3 M€

Amount of works:
100.6 M€